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A magnetic card compass is usually equipped with an optical, lensatic, or prismatic sight, which allows the user to read the bearing or azimuth off the compass card while simultaneously aligning the compass with the objective (see photo). Magnetic card compass designs normally require a separate protractor tool in order to take bearings ...
Parts of a hand compass. A hand compass (also hand bearing compass or sighting compass) is a compact magnetic compass capable of one-hand use and fitted with a sighting device to record a precise bearing or azimuth to a given target or to determine a location.
A bearing compass is a magnetic compass mounted in such a way that it allows the taking of bearings of objects by aligning them with the lubber line of the bearing compass. [79] A surveyor's compass is a specialized compass made to accurately measure heading of landmarks and measure horizontal angles to help with map making.
The construction of many early (mid-18th century) binnacles used iron nails, which were later discovered to cause magnetic deviations in compass readings. As the development of the compass and understanding of magnetism progressed, greater attention was given to binnacle construction to avoid compass disturbances caused by iron.
The simplest and most common type of hand compass has a horizontal compass rose and an observation device: a pinnule, alidade or viewfinder that allows the user to observe the target and then by "changing view", read the angle formed by the target's direction and the one marked by the compass with respect to the magnetic north.
The azimuth compass still had great value in letting the master of a ship determine how far the magnetic compass varied from true north, so he could set a more accurate course while following a line of constant latitude or using dead reckoning to navigate. In 1795 a British First Rate ship would have up to eight compasses, of which one was an ...
A circumferentor, or surveyor's compass, is an instrument used in surveying to measure horizontal angles. It was superseded by the theodolite in the early 19th century. [1] A circumferentor consists of a circular brass box containing a magnetic needle, which moves freely over a brass circle, or compass divided into 360 degrees.
A Brunton compass, properly known as the Brunton Pocket Transit, is a precision compass made by Brunton, Inc. of Riverton, Wyoming. The instrument was patented in 1894 by Canadian-born geologist David W. Brunton. [1] Unlike most modern compasses, the Brunton Pocket Transit utilizes magnetic induction damping rather than fluid to damp needle ...